4,088 research outputs found
Moleras en la Península Ibérica: una primera clasificación de las canteras de molinos
Este trabajo presenta una clasificación preliminar de moleras
(canteras de molinos) desde el punto de vista de la naturaleza
de la roca explotada (bloques de superficie o substrato rocoso) y
los medios de extracción. En un segundo nivel, se propone una
clasificación de moleras en base a criterios morfológicos, así como
las características resultantes de las técnicas de extracción. Esta
investigación se apoya en la observación de cuarenta yacimientos
identificadas en el sur de la Península Ibérica e incorpora datos de
la investigación de canteras molares (y canteras de sillares) llevadas
a cabo en otros lugares de Europa. Las circunstancias específicas
de las moleras y la elaboración de molinos en la Península Ibérica
durante la Edad de Hierro (el enfoque de la reunión realizada en
Arbeca, Lleida) siguen siendo en gran parte desconocidas, ya que
ninguna explotación de este periodo se ha identificado de forma
inequívoca en la Península. En este marco cronológico, no obstante,
es posible discernir tendencias sobre la elección de geomateriales
de una región a otra y especular acerca de la elaboración de
molinos en moleras
The Use of Silence as a Political Rhetorical Strategy
Existing research on the rhetorical strategies of politicians has mainly focused on the speeches, appearances, and debates of political figures. Yet the absence of a clear response when expected, or silence, is a significant and frequently utilized rhetorical strategy. More directly, Erickson and Schmidt (1982) posit that, even though it is important to study, the topic of political silence has only received meager attention. Various politicians including President Clinton and California Congressman Gary Condit have both used political silence as responses to situations, and each instance had a different outcome. The focus of this study is on how the strategy of silence fits into the tradition, examples of how contemporary politicians have used strategies of silence, and the development of criteria to evaluate the use of political silence. The major goal of this study is to examine the silence of the politician and use evidence to determine the effectiveness of that silence. Doing so will further enhance our understanding of political rhetorical silence as not just an absence of speech, but a rhetorical tool in its own right
Allatostatin-A neurons inhibit feeding behavior in adult Drosophila
How the brain translates changes in internal metabolic state or perceived food quality into alterations in feeding behavior remains poorly understood. Studies in Drosophila larvae have yielded information about neuropeptides and circuits that promote feeding, but a peptidergic neuron subset whose activation inhibits feeding in adult flies, without promoting metabolic changes that mimic the state of satiety, has not been identified. Using genetically based manipulations of neuronal activity, we show that activation of neurons (or neuroendocrine cells) expressing the neuropeptide allatostatin A (AstA) inhibits or limits several starvation-induced changes in feeding behavior in adult Drosophila, including increased food intake and enhanced behavioral responsiveness to sugar. Importantly, these effects on feeding behavior are observed in the absence of any measurable effects on metabolism or energy reserves, suggesting that AstA neuron activation is likely a consequence, not a cause, of metabolic changes that induce the state of satiety. These data suggest that activation of AstA-expressing neurons promotes food aversion and/or exerts an inhibitory influence on the motivation to feed and implicate these neurons and their associated circuitry in the mechanisms that translate the state of satiety into alterations in feeding behavior
The Use of Silence as a Political Rhetorical Strategy
Existing research on the rhetorical strategies of politicians has mainly focused on the speeches, appearances, and debates of political figures. Yet the absence of a clear response when expected, or silence, is a significant and frequently utilized rhetorical strategy. More directly, Erickson and Schmidt (1982) posit that, even though it is important to study, the topic of political silence has only received meager attention. Various politicians including President Clinton and California Congressman Gary Condit have both used political silence as responses to situations, and each instance had a different outcome. The focus of this study is on how the strategy of silence fits into the tradition, examples of how contemporary politicians have used strategies of silence, and the development of criteria to evaluate the use of political silence. The major goal of this study is to examine the silence of the politician and use evidence to determine the effectiveness of that silence. Doing so will further enhance our understanding of political rhetorical silence as not just an absence of speech, but a rhetorical tool in its own right
Estimating the Benefits of Water Quality Improvements in the Upper Narragansett Bay
An EPA-sponsored study of the benefits to Rhode Island residents of the water quality improvement in the Upper Narragansett Bay showed that the estimated annual costs (2.0 million). That analysis evaluated only user benefits which were measured via expenditures; nonuser (intrinsic) benefits were not included. This study estimated the benefits to Rhode Island residents using the "Contingent Valuation" approach and responses from 435 residents to a 1985 survey about swimming and shellfishing. Aggregate annual benefits were estimated to be in the range of 30-70 million for "shellfishable" water quality, depending on the type of measure (mean or median) and survey format. Secondary objectives of the study were to test different versions of "willingness to pay" questions and compare mean and median values for measurement. Aside from payment vehicle bias, we found no evidence of serious bias.contingent valuation, pollution, water quality benefits, Environmental Economics and Policy, Resource /Energy Economics and Policy,
Common Cause Failure Modes
High technology industries with high failure costs commonly use redundancy as a means to reduce risk. Redundant systems, whether similar or dissimilar, are susceptible to Common Cause Failures (CCF). CCF is not always considered in the design effort and, therefore, can be a major threat to success. There are several aspects to CCF which must be understood to perform an analysis which will find hidden issues that may negate redundancy. This paper will provide definition, types, a list of possible causes and some examples of CCF. Requirements and designs from NASA projects will be used in the paper as examples
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